ASUS PRIME B550M-K AMD B550 Micro ATX Motherboard
ASUS
ASUS PRIME B550M-K AMD B550 Micro ATX Motherboard
The ASUS PRIME B550M-K is a micro-ATX motherboard for AMD Ryzen processors, built for system builders who need a compact platform with modern storage and connectivity without paying for features they won't use. It delivers PCIe 4.0 support, dual M.2 slots, and comprehensive tuning controls in a smaller footprint.
Why this product
Dual M.2 with PCIe 4.0 support
The primary M.2 slot runs at PCIe 4.0 x4 on Ryzen 5000/3000 processors (PCIe 3.0 on 4000 G-Series), delivering 64 Gb/s bandwidth. The secondary slot runs PCIe 3.0 x4 for a second drive.
Micro-ATX form factor for smaller builds
At 9.6 × 8.7 inches, it fits compact cases and smaller desk footprints while retaining 4 SATA ports and full rear I/O.
Extensive cooling and tuning
Fan Xpert 2+ software and UEFI BIOS controls let you manage hybrid fan headers and monitor system temps under load. PCH heatsink keeps chipset stable during sustained workloads.
USB 3.2 Gen 2 on rear panel
Two Type-A ports at up to 10 Gbps give direct access to fast external storage and peripherals without front panel headers.
Broad Ryzen processor support
The AM4 socket accepts Ryzen 5000, 3000, and 4000 G-Series desktop CPUs. Check ASUS support list for your specific model.
- ChipsetAMD B550
- SocketAMD AM4
- Form FactorMicro-ATX (9.6 × 8.7 inches)
- Memory Slots4 x DIMM, up to 128 GB DDR4
- M.2 Slots2 (1 x PCIe 4.0 x4 on Ryzen 5000/3000; 1 x PCIe 3.0 x4)
- Rear USB 3.2 Gen 22 x Type-A (10 Gbps)
- SATA Ports4 x 6 Gb/s
- SKUASU-3400
- EAN4718017758284
- Fits AMD Ryzen 5000, 3000, and 4000 G-Series desktop processors in AM4 socket.
- Supports DDR4 memory up to 4600 MHz (O.C.) in dual-channel configuration across 4 DIMM slots.
- Accepts M.2 NVMe drives in 2242, 2260, 2280, and 22110 form factors (22110 only on primary slot).
- Supports standard ATX power supplies with 24-pin EATX and 8-pin 12V connectors.
- PCIe 4.0 M.2 bandwidth is available only on Ryzen 5000 and 3000 Series processors; Ryzen 4000 G-Series drops to PCIe 3.0 on the primary slot.
Best for
- Compact system builders who need PCIe 4.0 storage in a micro-ATX chassis.
- Users upgrading from older AM4 boards who want modern M.2 and USB 3.2 Gen 2 connectivity.
- Content creators and gamers with Ryzen 5000/3000 chips who benefit from PCIe 4.0 SSD speeds.
- DIY builders who want flexible fan and voltage tuning without paying for high-end RGB or WiFi.
Trade-offs
- ITX builds. This is micro-ATX, not mini-ITX; it will not fit ultra-compact cases.
- Ryzen 4000 G-Series with high-speed NVMe. The primary M.2 slot drops to PCIe 3.0, losing PCIe 4.0 bandwidth.
- Wireless networking requirements. It has wired Gigabit Ethernet only; no WiFi or Bluetooth onboard.
- Systems needing more than 4 SATA drives. The board maxes out at 4 SATA 6 Gb/s ports.
- Users needing USB-C on rear panel. All rear USB ports are Type-A; USB-C is not present.
AMD B550 (Ryzen AM4) micro ATX motherboard with dual M.2, PCIe 4.0, 1 Gb Ethernet, HDMI/D-Sub/DVI, SATA 6 Gbps, USB 3.2 Gen 2 Type-A
Comprehensive controls form the foundation of the ASUS Prime series. The Prime B550 motherboard packs flexible tools to tune every aspect of your system, enabling you to tweak performance settings to perfectly match the way you work – maximizing your productivity.
ASUS Prime series is expertly engineered to unleash the full potential of 3rd Generation AMD Ryzen platform. Boasting a robust power design, comprehensive cooling solutions and intelligent tuning options, Prime B550 series motherboards provide daily users and DIY PC builders a range of performance tuning options via intuitive software and firmware features.
Prime B550M-K is engineered with an array of hybrid fan headers and features comprehensive cooling controls that are configurable via Fan Xpert 2+ software or via the UEFI BIOS, ensuring your rig stays cool and stable under intense workloads.
General
| Brand | ASUS |
|---|
Processor & Memory
| CPU Socket | AMD AM4 (Ryzen 5000, 3000, 4000 G-Series) |
|---|---|
| Memory Type | DDR4 unbuffered, dual-channel |
| Memory Capacity | 4 x DIMM slots, max. 128 GB |
| Memory Speeds | 2133–4600 MHz (overclocked speeds supported) |
| ECC Support | Yes (varies by CPU) |
Storage & Expansion
| M.2 Slot 1 | PCIe 4.0 x4 (Ryzen 5000/3000) or PCIe 3.0 x4 (Ryzen 4000 G), also supports SATA mode, types 2242/2260/2280/22110 |
|---|---|
| M.2 Slot 2 | PCIe 3.0 x4 and SATA mode, types 2242/2260/2280 |
| SATA Ports | 4 x SATA 6 Gb/s, RAID 0, 1, 10 supported |
| PCIe Slots | 1 x PCIe x16 (Gen 4 on Ryzen 5000/3000, Gen 3 on Ryzen 4000 G), 2 x PCIe x1 (Gen 3) |
Connectivity & Audio
| Ethernet | Realtek RTL8111H, 1 Gb with LANGuard protection |
|---|---|
| Rear USB Ports | 2 x USB 3.2 Gen 2 Type-A (10 Gbps), 4 x USB 3.2 Gen 1 Type-A (5 Gbps) |
| Front Panel USB Headers | 1 x USB 3.2 Gen 1 (5 Gbps), 2 x USB 2.0 |
| Video Outputs | 1 x HDMI 2.1 (4K@60Hz), 1 x DVI-D, 1 x D-Sub |
| Audio Codec | Realtek ALC887/897, 7.1 surround, up to 24-bit/192 kHz playback |
| Audio Features | Shielded design, dedicated PCB layers, premium Japanese capacitors, S/PDIF output header |
Cooling & Power
| Fan Headers | 1 x CPU, 2 x chassis (hybrid, configurable) |
|---|---|
| Fan Control | Fan Xpert 2+ software and UEFI BIOS |
| Chipset Cooling | PCH heatsink |
| Power Connectors | 1 x 24-pin EATX, 1 x 8-pin 12V |
| System Protection | 5X Protection III (multiple hardware safeguards) |
Physical & Accessories
| Form Factor | Micro-ATX, 9.6 × 8.7 inches (24.4 × 22.1 cm) |
|---|---|
| Operating System Support | Windows 11, Windows 10 64-bit |
| Included Accessories | 2 x SATA cables, I/O shield, M.2 mounting screw package, user guide |
Shipping
All our products are shipped from the United Kingdom within 24 to 48 hours of purchase. See our Shipping and Returns page for full details.
Returns
- Tech Syndicate offers a full money-back guarantee on all purchases made in our store. If you are not satisfied with your purchase, we will provide a full refund, no questions asked.
- Refunds are available within 45 days of delivery.
- After the 45-day period you are no longer eligible for a refund, so we encourage you to try the product within the first few weeks to make sure it fits your needs.